AP BIOLOGY

Detailed explanation-1: -In most higher plants, the thylakoids are arranged in tight stacks called grana (singular granum).

Detailed explanation-2: -The Structure and Function of Chloroplasts In addition to the inner and outer membranes of the envelope, chloroplasts have a third internal membrane system, called the thylakoid membrane. The thylakoid membrane forms a network of flattened discs called thylakoids, which are frequently arranged in stacks called grana.

Detailed explanation-3: -Thylakoids are interconnected disc-like sacs of the internal membrane system of the chloroplast. They are found suspended in the stroma. Thylakoids are arranged in a stack, which is called grana. The thylakoid membrane contains the photosynthetic pigment chlorophyll, which absorbs the sunlight during photosynthesis.

Detailed explanation-4: -Chloroplasts contain a system of membrane sacs, the thylakoids, some of which are stacked to form grana (singular, granum), whereas others float freely in the stroma. It is on the thylakoid membranes that the electron carriers necessary for photosynthesis reside.